The U.S. added 151,000 jobs in August, slowing sharply from earlier in the summer and probably pushing an expected increase in U.S. interest rates toward the end of the year. Economists polled by MarketWatch had predicted 170,000 gain in new nonfarm jobs. The unemployment rate was unchanged at 4.9%. A broader measure of unemployment known as U6 was flat at 9.7%, the government said Friday.